Two things, Monks, I have realized: To never be complacent with skillful qualities; and not to shrink back from the struggle.

Without shrinking back, Monks, I struggle on thus:

Gladly would I have my skin and sinews and bones wither and my body’s flesh and blood dry up, if only I may hold out until I win what may be won by human strength, by human energy, by human striving.

It was by diligence that I achieved awakening, and by diligence that I won the supreme freedom from bondage (Enlightenment).

And you too, Monks, do not decline the contest, but struggle on, saying to yourselves: Gladly would I have my skin and sinews and bones wither and my body's flesh and blood dry up, if only I may hold out until I win what may be won by human strength, by human energy, by human striving; then you too, Monks, in no long time shall win that goal for which the Householders rightly leave home for the homeless life, even that unmatched goal of righteous living, realizing it for yourselves even in this very life; and having reached it you shall reside therein.

Wherefore I say unto you, Monks: Thus must you train yourselves: We will not decline the contest, but will struggle.

(Reference: AN 2.5)

In this Teaching from Gotama Buddha, he shares how it can be a struggle, at times, to attain Enlightenment. But through the struggle, there is much wisdom that is acquired that ultimately liberates the mind.

The Buddha shares “two things” that he realized, or learned, during his journey to Enlightenment.